Configurable integrated optical combiners and decombiners

Abstract

System, devices and methods are described that provide an integrated optical decombiner or optical combiner having both unamplified paths and amplified paths on which power monitoring and control may be located. A preferred multiplexing/demultiplexing optical path through the combiner/decombiner and a corresponding waveguide output/input is identified and optically coupled to a piece of fiber. Temperature control may be provided to tune an arrayed waveguide grating within the combiner/decombiner and minimize wavelength drift therein. Integrated power monitoring may be employed on one or more of the amplified waveguide paths to ensure that a preferred power level or range is maintained on an optical signal.

1. An integrated optical decombiner circuit comprising:
 an unamplified waveguide input configured to be optically coupled to an optical fiber for receiving a WDM signal; 
 an amplified waveguide input configured to be optically coupled to the optical fiber for receiving the WDM signal; 
 an input free space region that interfaces with the unamplified waveguide input and the amplified waveguide input; 
 a plurality of grating arms, coupled to the input free space free region; 
 an output free space region coupled to the plurality of grating arms, the output free space region having a plurality of waveguide outputs, each of the plurality of waveguide outputs supplying a corresponding one of a plurality of optical signals, each of the plurality of optical signals having a corresponding one of a plurality of wavelengths; and 
 wherein the unamplified waveguide input is associated with a first plurality of demultiplexing paths through the optical combiner circuit and the amplified waveguide input is associated with a second plurality of demultiplexing paths through the optical decombiner circuit. 
 
   
   
     2. The integrated optical decombiner circuit of  claim 1  wherein the input free space region, the plurality of grating arms, and the output free space region comprise an arrayed waveguide grating. 
   
   
     3. The integrated optical decombiner circuit of  claim 1  wherein a single input, selected from the amplified waveguide input and the unamplified waveguide input, is optically coupled to the optical fiber to define a demultiplexing path from among the first and second pluralities of demultiplexing paths for the WDM signal. 
   
   
     4. The integrated optical decombiner circuit of  claim 1  further comprising a temperature controller coupled to control a temperature of the integrated optical decombiner circuit. 
   
   
     5. The integrated optical decombiner circuit of  claim 4  wherein the temperature controller is coupled to a heater that controls the temperature of the integrated optical decombiner circuit. 
   
   
     6. The integrated optical decombiner circuit of  claim 1  wherein the amplified waveguide input comprises an integrated optical detector. 
   
   
     7. The integrated optical decombiner circuit of  claim 6  wherein the integrated optical detector comprises a tap coupler and photodetector. 
   
   
     8. The integrated optical decombiner circuit of  claim 6  wherein the integrated optical detector comprises an in-line photodetector. 
   
   
     9. The integrated optical decombiner circuit of  claim 6  wherein the integrated optical detector comprises an evanescent parallel photodetector. 
   
   
     10. The integrated optical decombiner circuit of  claim 6  wherein the integrated optical detector comprises a light scattered photodetector. 
   
   
     11. The integrated optical decombiner circuit of  claim 6  wherein the integrated optical detector comprises a resonator ring and photodetector. 
   
   
     12. The integrated optical decombiner circuit of  claim 6  further comprising a gain controller that controls a gain across the amplified waveguide input. 
   
   
     13. The integrated optical decombiner circuit of  claim 1  wherein the amplified waveguide input comprises a semiconductor optical amplifier. 
   
   
     14. The integrated optical decombiner circuit of  claim 1  further comprising a plurality of photodetectors, each of the plurality of photodetectors being associated with a corresponding one of the plurality of waveguide outputs, each of the plurality of photodetectors being configured to convert a corresponding one of the plurality of optical signals into a corresponding one of a plurality of electrical signals. 
   
   
     15. The integrated optical decombiner circuit of  claim 1  wherein the input free space region, the plurality of grating arms, the output free space region and the plurality of photodetectors are integrated on a single monolithic semiconductor substrate. 
   
   
     16. An integrated optical combiner circuit comprising:
 a plurality of waveguide inputs, each of which being configured to carry a corresponding one of a plurality of optical signals, each of the plurality of optical signals having a corresponding one of a plurality of wavelengths; 
 an input free space region, that interfaces with the plurality of waveguide inputs; 
 a plurality of grating arms, coupled to the input free space region, that transmit the plurality of optical signals; 
 an output free space region, coupled to the plurality of grating arms, that combines the plurality of optical signals onto an active waveguide output selected from a plurality of waveguide outputs; and 
 wherein the plurality of waveguide outputs comprises an amplified waveguide output and an unamplified waveguide output. 
 
   
   
     17. The integrated optical combiner circuit of  claim 16  wherein the input free space region, the plurality of grating arms, and the output free space region comprise an arrayed waveguide grating. 
   
   
     18. The integrated optical combiner circuit of  claim 16  further including a plurality of optical multiplexing paths provided between the input free space region and the output free space region. 
   
   
     19. The integrated optical combiner circuit of  claim 16  further comprising a temperature controller coupled to control a temperature of the integrated optical combiner circuit. 
   
   
     20. The integrated optical combiner circuit of  claim 19  wherein the temperature controller includes a heater. 
   
   
     21. The integrated optical combiner circuit of  claim 16  wherein the amplified waveguide output comprises an integrated optical detector. 
   
   
     22. The integrated optical combiner circuit of  claim 21  wherein the integrated optical detector comprises a tap coupler and photodetector. 
   
   
     23. The integrated optical combiner circuit of  claim 21  wherein the integrated optical detector comprises an in-line photodetector. 
   
   
     24. The integrated optical combiner circuit of  claim 21  wherein the integrated optical detector comprises an evanescent parallel photodetector. 
   
   
     25. The integrated optical combiner circuit of  claim 21  wherein the integrated optical detector comprises a light scattered photodetector. 
   
   
     26. The integrated optical combiner circuit of  claim 21  wherein the integrated optical detector comprises a resonator ring and photodetector. 
   
   
     27. The integrated optical combiner circuit of  claim 21  further comprising a gain controller that controls a gain across the amplified waveguide output. 
   
   
     28. A method for configuring an optical decombiner, the method comprising:
 monitoring an optical parameter associated with each of a plurality of optical signals, each of which propagating through to a corresponding one of a plurality of optical demultiplexing paths in the optical decombiner, each of the plurality of optical demultiplexing paths being associated with a respective one of a plurality of waveguide inputs; 
 selecting one of the plurality of optical demultiplexing paths; 
 coupling an optical fiber to one of the plurality of waveguide inputs, said one of the plurality of waveguide inputs corresponding to the said one of the plurality of optical demultiplexing paths; and 
 wherein the plurality of waveguide inputs comprises an amplified waveguide input and an unamplified waveguide input. 
 
   
   
     29. The method of  claim 28  wherein the configurable optical decombiner is integrated on the same substrate as a plurality of photodetectors. 
   
   
     30. The method of  claim 28  further comprising tuning a connection between said one of the plurality of waveguide inputs and an input free space region of the configurable optical decombiner by adjusting a temperature of the configurable optical decombiner. 
   
   
     31. The method of  claim 28  wherein the amplified waveguide input comprises a semiconductor optical amplifier and an integrated photodetection device. 
   
   
     32. The method of  claim 31  wherein the integrated photodetection device comprises an integrated photodetector selected from a group consisting of a tap coupled photodetector, an in-line photodetector, a parallel photodetector, a scattered light photodetector and a resonator ring photodetector. 
   
   
     33. An integrated optical decombiner circuit comprising:
 an unamplified waveguide input configured to be optically coupled to an optical fiber for receiving a wavelength division multiplexed (WDM) signal; 
 an amplified waveguide input configured to be optically coupled to the optical fiber for receiving the WDM signal; 
 an optical decombiner, having a plurality of inputs coupled to the unamplified waveguide input and the amplified waveguide input, that separates a plurality of optical signals from the WDM signal and transmits each of the plurality of optical signals on a corresponding one of a plurality of outputs; 
 a plurality of photodetectors coupled to the plurality of outputs to receive the plurality of optical signals, each of the plurality of photodetectors being configured to convert a respective one of the plurality of optical signals into a corresponding one of a plurality of electrical signals; and 
 wherein the unamplified waveguide input is associated with a first plurality of demultiplexing paths through the optical decombiner and the amplified waveguide input is associated with a second plurality of demultiplexing paths through the optical decombiner. 
 
   
   
     34. The optical decombiner circuit of  claim 33  wherein the optical decombiner and the plurality of photodetectors are integrated on a single semiconductor substrate. 
   
   
     35. The optical decombiner circuit of  claim 33  further comprising an electrical interface that allows a temperature controller to adjust a temperature of the optical decombiner. 
   
   
     36. The optical decombiner circuit of  claim 33  wherein the amplified waveguide input comprises at least one semiconductor optical amplifier that applies a gain to the WDM signal.